Using 802.11b and 802.11g simultaneously

I wanted to share this with everyone, since it took me a bit to set it
up. I was hoping that Linksys support would post it for public use,
but they so lost that's not even funny. They told me that this can
not be done.

Here's the story:

I upgraded my Wireless network from b to g, using Linksys Wireless G
accesspoint. All was working OK in G ONLY mode, until I got the
Linksys Wireless B camera and Wireless B Media Center. Since these
both work on B only, I had 2 choices:

1 - Run the Wireless G in "Mixed" mode, or as Linksys called it,
"BOTH" mode.
2 - Bring a Wireless B into my network.

My research concluded that Mixed mode is not good, since the signal on
the G drops to as low as 14MB, even though working in G. Yet, in
order to keep compatibility in Mixed mode, the G performance drops big
time.

Since I had my original B accesspoint, this is what I did:

-----------

1 Network, attached to a Linksys Cable Modem

Output of Cable Modem, goes in WAN port of WRT54G
WRT54G is setup for Channel 11 with different encryption key & SSID.
Wireless clients attach to this using G ONLY mode
Port 1 - PC
Port 2 - PC
Port 3 - attached to BEFW11S4 Wireless B accesspoint, port 1 (not WAN
port)

On BEFW11S4, I have a STATIC IP (192.168.1.120) setup which links it
to port 3 of WRT54G. DHCP is setup to dish-out only 20 IP addresses
from 192.168.1.160-180 BEFW11S4 is set for Channel 1 with different
SSID and encryption key (different than the WRT54G.)

Camera (192.168.1.115) is setup in the DMZ of the BEFW11S4 hard-coded.
The Media Center gets its IP address from B accesspoint using DHCP.

The Camera and media center attach to BEFW11S4 as a 802.11b clients,
then the traffic gets routed to the WRT54G via Ethernet on port 3.

54G clients stay at 54G, Camera and media center operate at 11MB using
802.11b. None of the clients interfere with another.

I'm sure there are other ways of doing this, but to keep the B and G
separate, this was what I came up with. I hope this helps someone who
might be in my situation.

Regards,
Sean

"Sean_a" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
>
> I upgraded my Wireless network from b to g, using Linksys Wireless G
> accesspoint. All was working OK in G ONLY mode, until I got the
> Linksys Wireless B camera and Wireless B Media Center. Since these
> both work on B only, I had 2 choices:
>
> 1 - Run the Wireless G in "Mixed" mode, or as Linksys called it,
> "BOTH" mode.
> 2 - Bring a Wireless B into my network.
<snip>

Option 3 is to use the USR5450 which does support b and g at the same time
with a good throughput. The problem with Linksys is that they use a chipset
which has a partial implementation of the 'b' support when working in 'g'
mode

"Tony Field" <(E-Mail Removed)> wrote in message
news:ndgyb.2$(E-Mail Removed)...
>
> "Sean_a" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed) om...
> >
> > I upgraded my Wireless network from b to g, using Linksys Wireless G
> > accesspoint. All was working OK in G ONLY mode, until I got the
> > Linksys Wireless B camera and Wireless B Media Center. Since these
> > both work on B only, I had 2 choices:
> >
> > 1 - Run the Wireless G in "Mixed" mode, or as Linksys called it,
> > "BOTH" mode.
> > 2 - Bring a Wireless B into my network.
> <snip>
>
> Option 3 is to use the USR5450 which does support b and g at the same time
> with a good throughput. The problem with Linksys is that they use a
chipset
> which has a partial implementation of the 'b' support when working in 'g'
> mode

Just a note... the USR8054 also supports b and g at the same time.

In article <ndgyb.2$(E-Mail Removed)>,
Tony Field <(E-Mail Removed)> wrote:

:"Sean_a" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed). com...

:> I had 2 choices:

:> 1 - Run the Wireless G in "Mixed" mode, or as Linksys called it,

:Option 3 is to use the USR5450 which does support b and g at the same time
:with a good throughput. The problem with Linksys is that they use a chipset
:which has a partial implementation of the 'b' support when working in 'g'
:mode

http://www.tomshardware.com/network/...botics-12.html

The other point of note is that the USR 11g card's throughput
dropped to about 12Mbps once an 11b station associated with the AP.
This is pretty much what I've seen with other 802.11g products.
What's different for USR is that it takes 15 minutes for throughput
to return to its higher (20Mbps) value once all 11b stations shut
down! This will be a moot performance point for folks who need to
run mixed 11b, b+ and g networks, but I'm not sure why this wait is
so long. Competitive APs typically take 1 minute or less to recover
once the last 11b client disassociates.
--
"Mathematics? I speak it like a native." -- Spike Milligan

No 802.11g networks function well in hybrid mode, which is what the original
poster was trying to get around. His solution is to setup two separate
networks on different channels, one "b" and one "g". That should work
perfectly, but involves more hardware.

According to Atheros
(http://www.atheros.com/pt/atheros_range_whitepaper.pdf, see table 1-1) the
theoretical best you can do in a hybrid environment is 14.4 mbps with
TCP/IP. These calculations are derived analytically from a probability
model, assuming 1500-byte packets, encryption, no frame errors, maximum
bitrate, and (I assume - it doesn't say) one transmitter. Results depend on
the protection method used. 14.4 mbps assumes "CTS-only", which means a
station sends CTS to itself before transmitting data. The other method is
full RTS/CTS, which takes much longer - throughput is expected to drop to
11.8 mbps. Not all pre-standard 802.11g clients use any protection at all,
and none of the 802.11b clients do. A hybrid net consisting only of clients
that use no protection is worst-case.

"Walter Roberson" <(E-Mail Removed)> wrote in message
news:bqd752$bq2$(E-Mail Removed)...
> In article <ndgyb.2$(E-Mail Removed)>,
> Tony Field <(E-Mail Removed)> wrote:
>
> :"Sean_a" <(E-Mail Removed)> wrote in message
> >news:(E-Mail Removed). com...
>
> :> I had 2 choices:
>
> :> 1 - Run the Wireless G in "Mixed" mode, or as Linksys called it,
>
> :Option 3 is to use the USR5450 which does support b and g at the same
time
> :with a good throughput. The problem with Linksys is that they use a
chipset
> :which has a partial implementation of the 'b' support when working in 'g'
> :mode
>
> http://www.tomshardware.com/network/...botics-12.html
>
> The other point of note is that the USR 11g card's throughput
> dropped to about 12Mbps once an 11b station associated with the AP.
> This is pretty much what I've seen with other 802.11g products.
> What's different for USR is that it takes 15 minutes for throughput
> to return to its higher (20Mbps) value once all 11b stations shut
> down! This will be a moot performance point for folks who need to
> run mixed 11b, b+ and g networks, but I'm not sure why this wait is
> so long. Competitive APs typically take 1 minute or less to recover
> once the last 11b client disassociates.
> --
> "Mathematics? I speak it like a native." -- Spike Milligan

In article <xEzyb.181$(E-Mail Removed) m>,
gary <(E-Mail Removed)> wrote:
:No 802.11g networks function well in hybrid mode, which is what the original
oster was trying to get around.

Right. My quotation from tomshardware was in relation to the statement
someone made that,

| Option 3 is to use the USR5450 which does support b and g at the same
| time with a good throughput.

tomshardware says the throughput in mixed mode for the USR5450
is not atypical, but that when mixed mode stops being true that
the USR5450 is slow to notice.

That would certainly lead -me- to hesitate before recommending
a USR5450 compared to some of the alternatives.
--
vi -- think of it as practice for the ROGUE Olympics!

"Walter Roberson" <(E-Mail Removed)> wrote in message
news:bqeiqj$1n3$(E-Mail Removed)...
> In article <xEzyb.181$(E-Mail Removed) m>,
> gary <(E-Mail Removed)> wrote:
> :No 802.11g networks function well in hybrid mode, which is what the
original
> oster was trying to get around.
>
> Right. My quotation from tomshardware was in relation to the statement
> someone made that,
>
> | Option 3 is to use the USR5450 which does support b and g at the same
> | time with a good throughput.
>
> tomshardware says the throughput in mixed mode for the USR5450
> is not atypical, but that when mixed mode stops being true that
> the USR5450 is slow to notice.

That's odd. The article talks about the Atheros-based and Agere-based
platforms having the slowest recovery times. Yet I find it hard to believe
that the problem is really in the chipset. I'll bet this is a driver or
adapter configuration thing that can be fixed with an upgrade. They mave
have set an anti-thrash timer too long, or something like that. It's pretty
easy to figure out that there are no more "b" clients in the net.

>
> That would certainly lead -me- to hesitate before recommending
> a USR5450 compared to some of the alternatives.

I'm not sure it matters much. If it's for home/SOHO use, you control the
client community. If it's for a hospot, how would the users know that they
should expect better performance? Say the last "b" user is named Elvis. How
do we know he's left the building?


> --
> vi -- think of it as practice for the ROGUE Olympics!